1. Field of the Invention
The invention relates to a plastic element used in electrical drives, especially in vehicles, and preferably in power window systems.
2. Description of the Prior Art
A plastic element of this kind is shown for instance in German Patent Disclosure DE 100 06 350 A1. The plastic element has multiple functions. It forms a bearing seat for receiving a shaft bearing, in particular a collar bearing, in a manner fixed against relative rotation, for a drive shaft connected to the rotor of a direct current electric motor in a manner fixed against relative rotation. In addition, the plastic element has at least two diametrically opposed commutator brush boxes, extending orthogonally to a shaft passage channel for the drive shaft. These commutator brush boxes serve to receive commutator brushes or current inverter brushes, also called carbon brushes, which rest, diametrically opposite one another, radially on a commutator seated on the drive shaft. The commutator brushes are supported displaceably inside the commutator brush boxes and are supplied with direct current. The commutator brush boxes serve to deliver current to the rotor winding.
In the known plastic element, the commutator brush boxes are passed directly through two parallel supporting arms for mounting the bearing seat for the shaft bearing. The problem is that vibration, especially in the acoustical, audible range, is transmitted from the commutator brushes, resting on the drive shaft or on the commutator, directly to the shaft bearing via the supporting arms of the bearing seat and from the shaft bearing to the gearbox, resting on the shaft bearing, of the electrical drive. The gearbox forms a resonant body for the vibration emitted by the commutator brushes, and this leads to unwanted noise production.